Table 1.

IC50s for inhibiting cyclooxygenases

IC50 (μM)	COX-2 in A549 cells*	COX-1(ovine)†	COX-2(human)†
9′-COOH	6 ± 2	>20‡	>20‡
13′-COOH	4 ± 2	5 ± 2	4 ± 2
γ-CEHC (3′-COOH)	35–70§	300 ± 50	450 ± 50
α-CMBHC (5′-COOH)	n.d.	160 ± 40	140 ± 40
Ibuprofen	5 ± 2	8 ± 2	5 ± 1
Acetaminophen	200 ± 50	>250‡	>250‡

The effect of purified 9′-COOH and 13′-COOH on COX activity was assayed in intact cells or using purified ovine COX-1 and human recombinant COX-2 (details described in Materials and Methods). Results were obtained based on two or three independent experiments and expressed as mean ± SD.

*The intact-cell assays were conducted in COX-2 preinduced A549 cells with 5 μM AA for 5 min.

^†Assays were conducted with purified enzymes in the presence of 5 μM AA for 2 min.

^‡9′-COOH and acetaminophen at 20 and 250 μM (the maximal concentrations tested), respectively, did not show any inhibitory effect on purified COX-1 or COX-2.

^§Previously reported (13, 21).

n.d., not determined.